The troposphere.

[islandwatcher]

The troposphere should contain 21% oxygen, 78% nitrogen and the remainder gases. However it now contains huge amounts of carbon dioxide, nitrogen dioxide, sulphur dioxide and carbon monoxide. I would imagine there has been some shrinkage.

[Tim S]

Yes there would be less oxygen I believe?? although this could also be attributed to the large deforestation of massive areas of our planets land surfaces.

As far as shrinkage goes, yes the top of the troposphere is rather cold so I'd imagine there would be major problems with shrinkage...

[islandwatcher]

The gases being emitted from various contraptions have lower atomic weights and molecular sizes than oxygen and nitrogen so would therefore occupy less of the space within the troposphere.

[Nev]

'Atmosphere of Earth' - Wikipedia

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere.

So even though CO2 levels are believed to have increased from about 0.028% since the Industrial Revolution, it's still a very, very small component of our atmosphere. That's not to say it (and other gases, which would be minuscule by comparison) don't have an effect on our climate, etc.

[islandwatcher]

Tim S identified one reason for the depletion of the troposphere. Trees are water pumps and they put huge quantities of water into our air. However, the never-ending commercial destruction of trees and bushes around the world has been in progress for at least 300-years that we know of. The missing water in our air had previously occupied space within the troposphere but we now have drought spreading around the world year-after-year like a cancerous disease.

[NZ Thunderstorm Soc]

I had an idealistic attitude that the wastage of certain points of the H20 cycle, when penetrated by the larger trees removal would tend a large reduction in the formidable gases that the atmosphere within certain levels would be able to maintain over a certain period, maybe 200 to 300 years in advance?
This depending on water evaporation?

[RWood]

Tim S identified one reason for the depletion of the troposphere. Trees are water pumps and they put huge quantities of water into our air. However, the never-ending commercial destruction of trees and bushes around the world has been in progress for at least 300-years that we know of. The missing water in our air had previously occupied space within the troposphere but we now have drought spreading around the world year-after-year like a cancerous disease.

You are only considering half of the story. A WMO warming scenario says this:

"...Global Precipitation

For a future warmer climate, the current generation of models indicate that precipitation will generally increase in tropical regions (such as the monsoon regimes) and over the tropical Pacific in particular. There is projected to be general decreases in the subtropics, and increases at high latitudes. Globally averaged mean water vapour, evaporation and precipitation are projected to increase."

[RWood]

Before you disappear - or the topic gets locked - your speculation about NZ sunshine levels is as far off the mark as one can imagine. The average NZ location receives 600-700 more hours of sunshine than the average UK one, and furthermore it is much stronger sunshine.

[Manukau heads obs]

The gases being emitted from various contraptions have lower atomic weights and molecular sizes than oxygen and nitrogen so would therefore occupy less of the space within the troposphere.

just because something sounds right, does not make it actually correct

it does not work that way

the atmosphere is a mixture of gases...molecular weights certainly do not come into effect (as everything is actually mainly space between molecules anyway)

However it now contains huge amounts of carbon dioxide

as has been pointed out, the CO2 levels are actually only in the parts per million only...dont see how you can say that is huge amount

but CO2, and more so carbon monoxide, are green house gases...trapping heat, and leading to a 'background' temperature offset globaly